Rf Output Connection; Dummy Antenna Information; Customer Interface Connections; Audio Input - Harris DX 25U Technical Manual

CAUTION
THE TRANSMITTER MUST BE GROUNDED WITH A LOW IMPED-
ANCE PATH. THE OUTER CONDUCTOR OF THE RF TRANSMIS-
SION LINE IS NOT AN ADEQUATE GROUND.

RF Output Connection

2.11
The RF output connection is a 3-1/8 inch gas barrier EIA flange
connector, (Female). A bullet and O-ring are provided and
packed separately. This combination allows mating to a male or
female transmission line connector. After the RF output termina-
tion is made, make sure the spark gap, E101 in the Output
Network Compartment, is set to 0.125 inches.

Dummy Antenna Information

2.11.1
It is very useful to be able to switch the transmitter RF output to
a dummy antenna for testing. This testing frequently includes
modulating with tones. With tone modulation, 100% modulation
of a 30 kW carrier produces an average power of 45 kilowatts.
Sustained asymmetrical modulation of a 25 kW carrier, with
-100% and +140% peaks, will produce 47 kW of average power
that must be absorbed and dissipated by the load. The instanta-
neous peak power under these conditions will be approximately
152 kW. When selecting a dummy load, select a power rating
WIRE # FROM TO
PA/OUTPUT CABINET INTERCONNECT
154 F17 2TB1-1
155 F18 2TB1-2
156 F19 2TB1-3
121 A27-J7 2J1
519 A27-J1 A26-J1
96 A17-J3 T6
STEP START PANEL INTERCONNECT
13TB1-1TB3-1SINGLE PHASE AC INPUT TO PA CABINET *
23TB1-2TB3-2SINGLE PHASE AC INPUT TO PA CABINET *
33TB1-3TB3-3GROUND
8 CONDUCTOR CABLE
SHIELD 3TB1-4TB3-4 **
BLK 3TB1-5TB3-5 **
BLU 3TB1-6TB3-6 **
BRN 3TB1-7TB3-7 **
GRN 3TB1-8TB3-8 **
ORN 3TB1-9TB3-9 **
RED 3TB1-10TB3-10 **
WHT 3TB1-11TB3-11 **
153TB1-15TB3-15K1 AND K2 COIL VOLTAGE
163TB1-16TB3-16K1 AND K2 COIL VOLTAGE
2 CONDUCTOR CABLE
SHIELD 3TB1-14 TB3-14
BLK 3TB1-17 TB3-17
WHT 3TB1-18 TB3-18
(Note: WHT may be clear or RED.)
Rev. AA: 8/9/2000
Table 2-3. Interconnect Wiring Check List
LOCATION/DESCRIPTION
OUTPUT NETWORK CABINET
SAME
SAME
SAME
OUTPUT SAMPLE BOARD IN OUTPUT NETWORK CABINET
PA CABINET, PA COMBINER OUTPUT BAR AND COVER ASSEMBLY
888-2297-002
WARNING: Disconnect primary power prior to servicing.
sufficient for the type of testing to be done. The peak power
should be considered when selecting a water cooled load.

Customer Interface Connections

2.12
The following paragraphs include information on customer in-
terface connections for:
•

Audio Input

•
Frequency and Modulation Monitors
•
External Interlocks
•
External RF Input
Refer to paragraphs on Remote Control connections for a de-
scription of various interface connections.
Audio Input
2.12.1
Use a shielded pair audio cable for connection between process-
ing equipment and Audio Input terminal TB3 on the External
Interface. The External Interface is located at the top of the right
side wall in the Center Control Compartment.
Audio input connections are as follows:
•
TB3-1: Shield (to transmitter chassis ground).
•
TB3-2: Audio (+)
* NOTE: #1, #2, & #3 are 14 AWG. Electric
code may require different wire size being
used.
** NOTE: This is only a suggested order to follow.
The color coding may vary between different wire
manufactures. (e.g. BRN substituted with
RED/BLK. YEL substituted with WHT/BLK.
The important thing is to maintain the 1 to 1
interconnect between 3TB1 and TB3.)
NOTE: YEL or 8th does not need to be connected.
Section II - Installation
2-5